The Titans have needed a defensive end for some time now, but with them potentially shifting to a 3-4 or at least something more akin to a 3-4, they need to pick up an end who can play in that scheme.
Right now, Derrick Morgan, Lavar Edwards and Karl Klug could fit in the spot, but none are excellent fits, and only one is a reliable enough starter not to be a concern going forward. Because of that, the Titans may spend a high pick on a player who better fits the 3-4 scheme at the end position.
If they were use their top pick, the best fit would be Notre Dame's Stephon Tuitt. Despite his size, he has been an effective pass-rusher for the Irish his whole career, and at 6'6" tall and 312 lbs, he has prototypical size for the position.
He was better in 2012 than 2013, but he was great both years, amassing a total of 94 tackles, 20 tackles for loss, 18.5 sacks, 22 quarterback hurries, three defended passes and two forced fumbles.
He could play in either the 4-3 or the 3-4 too, so he has the versatility that the Titans crave.
If they were decide to spend a later pick on the position, Kareem Martin of North Carolina could be a good value in the middle rounds. He provides the same kind of versatility, although he'd need to gain some weight to play 3-4 end.